This invention relates to technology for maintaining security of cellular phones.
Accompanying their ever advanced functions, the cellular phones are finding diversifying applications, such as a data (packet) communication terminal for carrying out electronic mails, chatting and internet browsing, that have evolved from module of speech, a database for the management of classified telephone directory and personal schedule data, as well as a game device and a simple digital camera. It is further becoming possible to obtain and watch the images and musical contents. In purchasing these contents, settlement can be done by using the cellular phone.
As described above, the cellular phone is capable of managing a variety of personal data related to the owner of the phone and conducting the settlement, and thus offers functions equivalent to the cash and credit cards. It, therefore, becomes necessary that the cellular phone is equipped with a mechanism which prevents the use by a third person without authentication, that would happen in case the cellular phone is tampered with, lost or is stolen.
On the side of the owner of the contents who delivers images and music to the cellular phones, on the other hand, a mechanism is necessary which guarantees that the cellular phone has been used by a normal registered user to prevent such an occurrence that the service is received by the unauthorized person.
There have been proposed many cellular phones equipped with a mechanism for preventing the unauthorized use. The method employed by these phones is to authenticate that the user of the cellular phone is a true owner by utilizing any one of biodata (such as fingerprint, voiceprint, retina) inherent in the owner who has been registered to the cellular phone in advance, or by utilizing a combination thereof. Concretely speaking, according to the cellular phone disclosed in Japanese Patent Laid-Open No. 284182/1994, the security control unit registers and collates the fingerprint by controlling a fingerprint reader unit, a fingerprint registering unit, a fingerprint collation/comparator unit and a fingerprint temporary storage unit being triggered by the operation of the security button and the power source switch and, further changes the security state. For example, when the user explicitly depresses the security button in a secure state where the power source circuit is closed and the telephone function is active enabling speech to be conducted, the fingerprint of the user is obtained and is compared with the fingerprint data that have been registered in advance to verify it. When it is authenticated that the user is the owner, it is allowed to use the normal telephone function. In other cases, the button operation is locked to prevent the use without authorization.
The cellular phone disclosed in Japanese Patent Laid-Open No., 165378/2000 is equipped with both a fingerprint authentication unit and a voiceprint authentication unit, the fingerprint authentication unit being provided in the power source switching unit. Therefore, the power source circuit is not closed unless the fingerprint is authenticated. The voiceprint authentication is also conducted, and the speech is not permitted unless the two forms of authentication are in agreement. Even when the speech is started, further, the power source circuit is opened when a predetermined period of time has passed to prevent the use without authorization.
Here, when the data of fingerprint only is used for authenticating the user of the cellular phone, it is not possible to distinguish whether the fingerprint of the owner of the cellular phone is that of his finger or the one copied onto an artificial material such as of silicon. Therefore, there remains a probability in that a person with evil intention other than the owner may succeed in getting the authentication. Hence, the safety is not sufficient.
According to the prior art, further, the user of the cellular phone must explicitly execute the authentication operation by depressing the security button for each use. When the security button is not depressed, the owner is judged to be an unauthenticated user and, as a result, limitation is often imposed on the functions that can be used. Namely, authentication requires cumbersome operation and makes it less easy to use the cellular phone.
Further, even when it is authenticated that the user is the owner of the cellular phone, the power source circuit is broken after the passage of a predetermined period of time for maintaining safety. Therefore, it is not allowed to sustain the waiting state for receiving a call at any time greatly spoiling one of the convenient features of the cellular phone. Further, the authentication operation is carried out at regular intervals irrespective of that the owner is now using the cellular phone. Namely, the authentication operation is conducted unnecessarily wastefully consuming the electric power. This shortens the operation time of the cellular phone that is powered by a battery. Thus, the authentication function, too, makes it less easy to use the cellular phone.
This invention therefore provides a cellular phone equipped with a security function which automatically and reliably authenticates the user and limits, the function of transmission when the user is not the owner, and offers a sufficient degree of safety relying upon a minimum degree of authentication operation.
The cellular phone provided by the invention comprises:
an antenna for transmitting and receiving electromagnetic waves;
a speaker for producing a voice of a distant person and for letting the user know a call;
a microphone for picking up a voice;
operation keys for inputting telephone numbers and for turning the power source circuit on and off;
a display unit for displaying a telephone number and the content of an electronic mail;
a memory for storing a-classified telephone directory and a software program;
a display control unit for controlling the display unit;
an operation control unit for controlling the function of the cellular phone depending upon an instruction from the operation keys and upon the authentication condition and for executing the application programs;
communication module for transmitting and receiving speech and data (packet);
use detection module for judging the state of contact to the user by measuring the temperature; and
personal authentication module for authenticating that the user of the cellular phone is the owner.